WASHINGTON -- A 25-year-old woman seeking health insurance in North Carolina on her own could expect to pay $60 to $300 a month for her coverage.

Her twin brother? Up to 50 percent less.

North Carolina is one of all but about a dozen states that still allow health insurance companies to consistently charge women more than men for the same coverage.

The practice, known as gender differentiation, could be banned under nearly all of the health overhaul bills now being considered in Congress.

A Charlotte Observer/(Raleigh) News & Observer review of health premiums in North Carolina found that until patients reach their 50s, women are consistently charged more than men.

For example, a Blue Cross Blue Shield comprehensive policy, with a $2,500 deductible, would cost a 38-year-old Durham man $182 a month. For a woman of the same age and hometown, the cost jumps to $269, or more than $1,000 a year. Add optional maternity coverage, and the monthly premium leaps to $490.

Prices were similar at other insurance companies, including Aetna, UnitedHealthOne, CoventryOne and Celtic.

The companies say the differential makes sense because women routinely cost more to care for than men, especially at child-bearing age. In older adults, men use more health services and cost more than women.

"It used to be that insurance companies charged by race, and that fell away as a reason to charge differential premiums, and we think it is time that gender rating disappeared, as well," said Judy Waxman, vice president of health and reproductive rights at the National Women's Law Center in Washington.

Michelle Titsworth of Greensboro shopped around this year for health insurance but found nothing she could afford.

Getting insurance through her part-time job as a library assistant would have cost $200 a month. Adding herself to her husband's health plan, which already covers the couple's three young children, would cost even more, she said.

"With bills and everything, we would be in the negative," said Titsworth, 26, whose husband works two jobs. "We're barely making it right now."

Titsworth was frustrated enough to write U.S. Sen. Kay Hagan of North Carolina last spring to complain about how the system seems to impact women. "I can't afford it for myself," Titsworth said. "Me as a woman - that I can still have babies - it's a lot pricier."

This month, Hagan joined several female senators in pushing for a health bill that they say would treat women more fairly. Last week, she spoke on the Senate floor about how her grown daughter would be charged more than her son because of her gender.

"I think the equal premiums for equal coverage is what we're looking for under health care reform," Hagan said.

There are other issues affecting women.

Among the pre-existing conditions that can be used to deny coverage to women on the individual health insurance market are pregnancy and previous Caesarian sections.

"You have to think the way insurance companies think," Waxman said. "If you've had a C-section once and want to have another child, you may have a C-section twice. They think, 'You've had a C-section. We're upping your premiums, or we're not covering you for maternity. It costs too much.'"

The National Women's Law Center also lists North Carolina among eight states that do not specifically prohibit domestic violence as a pre-existing condition.

The state's Department of Insurance, which regulates health insurance companies, disputes that claim.

State law only allows insurance companies to use actual medical conditions as pre-existing conditions, said Kristin Milam, spokeswoman for the department. That wouldn't include domestic violence, she said. Plus, she added, the office reviews companies' application forms to ensure that the questions are appropriate.

Calls to companies that sell individual plans in North Carolina either were not returned or referred to the state or the national group that represents health insurance companies.

"What we know is that at younger ages, women use more health care services than men, and that's reflected more in the premiums they pay," said Robert Zirkelbach, spokesman for America's Health Insurance Plans in Washington.

Ted Hamby, a deputy commissioner at the state Department of Insurance, said many services are based on women's gender, including gynecological care, cervical cancer screenings and mammograms.

Both said the trend reverses as patients age, with men eventually charged more.

The newspapers' review found that for many individualized health insurance plans, men begin to cost more than women once they both reach their fifties. A quote from Blue Cross Blue Shield of North Carolina showed men cost more and are charged moremore than women at age 61.

Medicare, the government health-care program for senior citizens, kicks in at age 65. So the period during which men pay more than women is relatively short.

Zirkelbach said his group supports ending gender differentials for health plans, as long as the health overhaul includes mandated coverage for everyone. Universal coverage would provide companies more business, he acknowledged, but it would help patients, as well.

"To make that work, we need everyone to participate," Zirkelbach said. "It's good for everybody if we can get a system where everybody's getting the health care they need at an early stage."